Rotational die stamping tool

ABSTRACT

The present die stamping tool has a baseplate shaped to conform to the surface of a rotational body, such as a cylinder. Working blades are held in grooves or slots of the baseplate by means of serrated back edges which may be provided with gripping teeth. The rotational die stamping tool is made by shaping or bending the baseplate, cutting said grooves or slots, serrating the back edges of said working blades and anchoring said serrated back edges in the grooves or slots.

United States Patent Inventor Ernst Maximilian Spengler Bergen-Enkheim,Germany App]. No 731,535

Filed May 23, 1968 Patented Mar. 16, 1971 Assignee Roeder & Spengler OHBBergen-Enkheim Hessen, Germany Priority May 24, 1967 Germany ROTATIONALDIE STAMPING TOOL 5 Claims, 28 Drawing Figs. I

US. Cl 83/663, 76/107, 83/665, 83/698 Int. Cl B26d l/l2 Field 01' Search83/663,

Primary Examiner- Frank T. Yost Attorney-Wolfgang G. Fasse ABSTRACT: Thepresent die stamping tool has a baseplate shaped to conform to thesurface of a rotational body, such as a cylinder. Working blades areheld in grooves or slots of the baseplate by means of serrated backedges which may be provided with gripping teeth. The rotational diestamping toolis made by shaping or bending the baseplate, cutting saidgrooves or slots, serrating the back edges of said working blades andanchoring said serrated back edges in the grooves or slots.

Patented I March 16, 1911 3,570,355

4 Sheets-Sheet 1 Patented March 16, 1971 4Sheets-Sheet J S QW WWWMWWWROTATKGNAL THE STAMPING TOOL The present invention related to rotationaldie stamping tools and to methods of making such tools which are usedfor die stamping, grooving, slitting, cutting or similarly outlining ofshapes, especially of contours or shapes or configurations made ofpaper, cardboard or the like. Such shapes may be used to make, forinstance, packaging cartons.

Prior art die stamping tools for the above purpose comprise cuttingblades inserted, in the desired shape configuration, into plain baseplates of synthetic, plastic or similar material. The desired shapeconfiguration or outline is cut into the known plates by means of ajigsaw. The outlines cut by the jigsaw are interrupted at suitablespacings by bridge members so as to hold the plate portion the outlinesof which constitute the shape configuration, in place in the plate.

The working blades of such tools are made of band steel, a working edgeof which is sharpened while the opposite or back edge is inserted intothe jigsaw cut shape configuration. Due to said bridge members theblades are provided with indentations having a depth corresponding tothe width of the base plate and they are broad enough to accommodate thebridge members thus preventing that the bridge members interfere withthe insertion of the blades. The back edge of the blades usually extendsfully through the base plate but does not protrude therefrom. The platesare attached to the stamping member of a stamping press and thesharpened edges of the blades protrude from the base plate to anextend'corresponding to any desired cutting depth.

Due to the plain base plate prior art die stamping tools are notsuitable for a rotational cutting motion and are thus limited to areciprocating cutting motion.

It is an object of the invention to increase the operating speed of suchdie stamping tools.

Another object is to provide a rotational die stamping tool which may beoperated by means of a rotating member rather than by a reciprocatingstamping member.

Yet another object is to provide a method for making such rotational diestamping tools suitable to be attached to a rotating drum.

According to the invention the above objects have been attained byproviding a base plate which is bend to conform to the periphery orcircumference of a rotational body, such as a drum or cylinder, and intowhich working blades are inserted having a serrated back edge.

A particularly advantageous embodiment of the invention comprises teethalong the back edge, which have anchoring hooks or recesses which may bebend out to protrude from or be inserted within the plane of the teeth.

The serrations of the back edges may have quite closely spaced teeth andthe spacings between adjacent teeth may have bottoms of predeterminedshape, for example, the bottoms may have corners, especially straightcorners, or they may have a circular or heart shape.

The cutting blades are preferably provided with apertures between theworking edge and said serrations which apertures improve the bendabilityof the blades as well as the bendability of the entire shape or contouroutlined by the blades thus facilitating the bending of the blades inconforming them to the rotational base plate which may be made of metalsuch as aluminum, brass, bronze or the like, or of thermoplasticmaterial, such as hard polyvinyl chloride or a heat curable syntheticmaterial. The width of the base plate and its strength and/or othercharacteristics will be selected in such a manner that the insertedworking blades are securely held in the base plate and any bending downis avoided.

According to the invention there is further provided a method for makingthe above-mentioned die stamping tools wherein a base plate is bent toconform to the diameter, or rotational shape of a rotational body, suchas a cutting roller, the base plate is then provided with radiallyextending incisions outlining the desired contour to be cut and workingblades which have been prepared as a band having a serrated back edgeare then inserted with such back edge into said incisions whereupon theback edge is securely anchored in the material of the base plate wherebythe working blade or band is shaped to conform in space to the desiredrotational surface.

The incisions in the base plate may be made in any known manner, forexample, by means of a jigsaw or by a heat treatment. However, theinvention teaches that the incisions should extend radially relative tothe rotational body along the entire length of a blade, that is theincisions should extend exactly perpendicularly relative to the bentsurface of the base plate.

The anchoring of the serrations in the base plate could, for example, bygluing or by a heat treatment of the base plate or by filling the spacesbetween the teeth of the serrations with a filler material while theserrations are properly inserted and in position in the incisions of thebase plate.

Another possibility of anchoring the cutting blades in the base plate isprovided by the invention in that the blades have anchoring hooks in theteeth of the back edge. Such blades are first formed into, a desiredrotational configuration, for instance, by a pressure or hammeringtreatment, and then the anchoring hooks are forced into the incisionsthus securing the blades in its base plate.

Although the present specification speaks mostly of cutting blades it isto be understood that the invention is not limited to cutting butincludes any die stamping tools such as are used, for example, forgrooving, slitting, perforating or any other manner of producing acontour or outline on a work material.

In order that the invention will be clearly understood it will now bedescribed, by way of example, with reference to the accompanyingdrawings, wherein:

FIG. 1 is a perspective view of a rotational diecutting tool;

FIG. 2 shows a sectional view along the line II-II of FIG. 1;

FIG. 3 illustrates a front view of a bent cutting blade;

FIGS. 4 and it show side and front views of a cutting blade which is notbent;

FIGS. 5, 5a 6, 6a, 7 and 7a illustrate front and side views of yet otherembodiments of cutting blades whereby the blade of FIG. 5 is not bent;

FIGS. 8 and 8a show side and front views of a blade having aperturestherein throughout its length;

FIGS. 9, 9a and 912 show a blade with anchoring hooks in the I teeth ofthe serrations said hooks extending into the spaces between the teeth asshown in more detail in FIGS. 14, 14a, and Mb;

FIGS. 10, 10a and 10b illustrate anchoring hooks made by stamping,extending out of the teeth as shown in detain in FIGS. 15, 15a and 15b.

FIGS. Ill and 12 show perspective views for explaining the insertion ofa blade into the base plate; and

FIG. 13 shows a sectional view of a blade as it is being inserted intothe base plate,

FIGS. 14, Ma and 14b show the details of the blade of FIGS. 9, 9a and 9bFIGS. 15, l-5a and 1412 show the details of the blade of FIGS. 10,10a,and 10b.

FIGS. 1 and 2 show a rotational die stamping tool having a base plate Iof suitable material which is bent to conform to the circumference of astamping drum. Cutting blades 2 are inserted into the base plate along adesired contour or outline. The blades 2 bound areas 3 which correspondto the shapes or contours or configurations to be die stamped out ofpaper, fabric or the like.

The base plate may be made of any material which is suitable to assure asufficient holding of the inserted blade. If necessary, the base platemay thus be made of aluminum, brass, or even of a suitablesteel.Further, suitable heat curable synthetic materials, hard papers or woodmay be used to make the base plate. l-Iard polyvinyl chloride has beenfound suitable for most uses here involved.

The thickness of the base plate depends upon the required height ordepth of the working blades. The larger the cutting depth will be thehigher will be the height of the blades so that only a sufficientlythick base plate will prevent the bending down of the blades unless avery hard or strong base plate material, such as steel or the like isused.

Even where the rotational die stamping tool according to the inventionis in the form of a grooving, slitting, perforating, corrugating orserrating blade, it is advantageous to secure these blades in the baseplate in the same manner as described above. Such blades may, just asthe cutting blades, be made of preformed band steel. The band steel willhave the same strength as that used for making conventional plane diestamping tools. Such strength or width will be in the order of 0.5millimeter to 2 millimeter, and mainly 0.7 millimeter to 1.0 millimeter.The ratio between the full height of a blade and its desired cuttingdepth will depend upon the material of which the base plate is made aswell as upon the width of the blade.

The base plate 1 with the cutting blade 2 inserted therein, will besecured to a rotational cylinder (not shown). The material to be cutwill be passed in suitable manner at constant speed under the cylinderand in contact therewith. Whereby the rotational stamping tool orcutting blade will roll over the material to cut out the desired shapeor contour.

It is an important advantage of the invention that the necessary cuttingpressure is substantially lower than for plane die stamping toolsbecause due to the rotational cutting action it is now not necessary topress down simultaneously the entire blade configuration. Thus thepressure can now be concentrated along a line where the instantaneouscutting action takes place.

Yet another advantage is the substantially higher working speed of thepresent tools as compared to plane tools because no reciprocating toolmotion is necessary. Thus the entire tool motion (rotation) is effectivefor the cutting operation and not just the down stroke as in prior arttools.

The material stamped out in the desired configurations will occupy aspace or area 3 bounded by the cutting blades and will be removed in anysuitable manner after a cutting run is completed. For example, wellknown pushout members may be inserted into the areas 3, for example,foam rubber pads will facilitate the pushout function.

Where the cutting blades do not extend in parallel to the longitudinalaxis of the rotational cylinder, it is necessary to conform the blade tothe arc corresponding to the surface of the cylinder to which the bladeis attached through its base plate. Such conforming of the blades to therotationed body would cause tensile forces in the cutting area of ablade and compressional forces in the back edge of the blade. Theinvention obviates this difficulty and greatly facilitates the bendingnecessary for such conforming by providing the back edges of the bladeswith serrations.

Such serrations include spacings 6 between adjacent teeth. The spacingsprovide sufficient flexibility in the areas which otherwise would besubject to compressional forces and thus the bending is made possible atall. The shape of the teeth may vary as desired, for instance, as shownin FIGS. 3 to a. In the embodiment of FIG. 4 the spacings 6 arerelatively wide as compared to the width of teeth 5. Contrary theretothe spacings shown in FIG. 6 are of relatively narrow width. Where thespacings 6 have a squared straight line boundary as shown in FIG. 7,their width can be still smaller, this will depend upon the amount ofbending required for conforming the blades to the surface of thesupporting rotational body.

It has been found that especially desirable bending conditions arerealized if the teeth are formed as show in FIGS. 4, 5, 9 and 10 whereasgood stress distribution is accomplished with serrations having spacingssuch as shown in 5 and 7 to 10. In any event the bending is greatlyfacilitated by the serrations as taught by this invention.

FIG. 8 shows that the spacings 6 between teeth 5 are bounded by straightlines and are relatively narrow. To still further improve the bendingcharacteristics of the blades, apertures S are provided in the bladesbetween the cutting edge and the serrated back edge.

FIG. 9 illustrates a serration in which the teeth 5 have anchoring hooks7 which protrude alternately from the side of the teeth which faces anadjacent tooth. The hooks may point up and down in alternating fashion.The hooks may be completely within the plane defined by the blade orthey may protrude from such plane in alternate fashion as shown in FIG.I

9a in more detail.

FIG. 10 shows a modification of the hooks 7 in that the hooks protrudein alternate fashion from one or the other surface ofa plane defined bythe blade.

The method of making a die stamping tool according to the invention willnow be explained with reference to FIGS. 11 to 13.

One or more curved base plates 10 having an inner radius of curvaturecorresponding to the outer radius of a pressure roller (not shown) maybe suitably attached to such roller.

First incisions 11 are made in the surface of the base plate,

such incisions 11 corresponding to the pattern, shape, contour orconfiguration to be cut out of a material, for example, carton blanks.The incisions ought to extend radially into the base plate at all pointsalong the length of the incisions. This may be accomplished, forinstance, with a special jigsaw the saw blade of which is guided in sucha manner that the saw blade will always extend at a right angle to thecurvature (radially). However, it is also possible to make the incisionsin any other suitable manner, for example, by a heat treatment of thebase plate or by using other suitable tools.

The incisions 11 may extend completely through the base plate 10 wherebythe areas bounded by the incision are prevented from falling out of thebase plate by means of bridging members.

The incisions may also be made in the form of a series of cuts ofrelatively short length or holes whereby the length of such cuts orholes will depend upon the size of the teeth of the blades to beinserted therein.

A working blade previously made of band steel will now be inserted intothe contour of the incisions 11. Such insertion may be accomplished byhammering, pressing or rolling or a combination thereof.

The cutting blades l2 will be bend or shaped in space as they are beinginserted to follow the curve of the base plate so that at any particularpoint the blades extend perpendicularly to the curved surface of thebase plate 10 that is, the blades will protrude radially relative to thecenter axis 14 of the base plate 10.

As shown in FIG. 11 the blade 12 has been inserted up to the point 13.

After the insertion of the blades in the prepared incisions the spacingsbetween the teeth 5 may be closed, for example, by a heat treatment ofthe material of the base plate or by filling such spaces with a suitableglue so that the blades will be securely held in the base plate. Insteador in addition the surfaces of the incisions may be coated, either prioror during the insertion, with a suitable glue which, after hardening,will hold the blades in the base plate. No gluing is necessary withanchoring hooks but hooks and gluing and/or heat treatment may be usedin combination.

The hooks alone will hold the blades in the base plate with sufficientstrength so that a closing or filling of the spaces is not absolutelynecessary. However, gluing etc. may be used as additional strengtheningmeans, particularly where the base plate is relatively thin or where arelatively high cutting depth IS necessary.

Stress relief bores 15 may be provided adjacent the incision in anyknown manner.

It is preferable to attach the base plate to a curved work support whichis rotatable about a vertical axis.

It is to be understood that the invention is not limited to theparticular embodiments and features described and shown but alsocomprises any modifications with the scope of the appended claims.

I claim:

I. in a rotational die stamping tool having a preformed base plateconforming to the surface of a rotational body and a working blade meansheld in slots in said base plate said working blade means defining aplane and having a working edge protruding above the surface of the baseplate as well as a serrated back edge with teeth anchored in said slotsof the base plate, the improvement comprising anchoring hooks formingpart of at least some of said teeth, said anchoring hooks having adownward slant to form a downwardly pointed surface for facilitating theinsertion of the serrated back edge of the blade means into said slots,said anchoring hooks further having an upwardly facing surface forfacilitating the anchoring of the blade means in said slots.

2. The rotational die stamping tool according to claim 1, wherein saidanchoring hooks protrude out of said plane

2. The rotational die stamping tool according to claim 1, wherein saidanchoring hooks protrude out of said plane defined by said blade means.3. The rotational die stamping tool according to claim 2, wherein saidhooks are bend out of said plane defined by said blade means inalternate fashion whereby said downwardly pointed surfaces and theupwardly facing surfaces appear on each side on every other of saidteeth.
 4. The rotational die stamping tool according to claim 1, whereinsaid base plate is made of a heat treatable material.
 5. The rotationaldie stamping tool according to claim 1, wherein serrations betweenadjacent teeth have a heart-shaped bottom opening downwardly.